<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script type="text/javascript">

    var a=1;
    var b=2;

    var c=a;
    a=b;
    b=c;
    onsole.log("b ="+b);
    console.log("a ="+a);

</script>
</body>
</html>